| 摘要 |
<p>The invention relates to an electro-protective and corrosion-protective device meant for the controlled protection of underground metal pipelines prone to A.C. polarization, i.e. an electro-protective device for polarized electrical disconnection of a metal structure, such as a metal pipeline operating in a natural electrolytic medium and prone to electric corrosion. According to the invention, the device comprises a packaged double transitory voltage limiting structure (1.1), a packaged high power Zener structure (1.2) and a packaged high power Schottky structure (1.3), as well as some bleeder resistors (1.4 and 1.5) by which the interconnection of said structures is achieved, there being obtained a voltage-current characteristic with a very small opening voltage, in the range of 0.2 V in direct polarization, while in the reverse polarization this is limited to the range of 2.0...3.0, which is secure for the corrosion-preventive insulations applied to metal structures.</p> |
